Xiph QuickTime Components (XiphQT) is, in short, the solution for Mac and Windows users who want to use Xiph formats in any QuickTime-based application, e.g. playing Ogg Vorbis in iTunes or producing Ogg Theora with iMovie.
MPEG Streamclip is a powerful video converter, player, editor for Mac and Windows. It can play many movie files, not only MPEGs; it can convert MPEG files between muxed/demuxed formats for authoring; it can encode movies to many formats, including iPod; i